An Online RPG can either be a game like Diablo 2 where you buy it offline then play it online or it can be an online-only RPG that is either played in a browser and/or does not have the subscription model of MMORPGs. Most of the time, Online RPGs that fit into this latter category are free and a large number of them are text-based. 

Free MMORPGs 
Check out free multiplayer games on a massive scale.

Top 10 Online RPG List 
See which Online RPGs are ranked the best by GameOgre.com.

Free Online RPGs

Runescape
Graphics: 3D
Download: No, Browser.
Needs to be bought: No, but has premium version available.
If you want to play a fantasy online RPG with huge masses of people then its hard to beat Runescape. This game has both free and premium plans.

HoboWars
Graphics: Text
Download: No
Needs to be bought: No
Very original browser-based RPG where you take on the role of a hobo that explores cities doing various activities such as begging, gambling, and fighting. 

Ninja Wars Graphics: Text Download: No Needs to be bought: No Allows you to portray a mystic ninja who wages war with clans and other ninjas. One interesting way to earn money is to collect bounties on the heads of other ninjas. Vote for the Online RPG of 2010 Nominate and vote on your favorite games!

Diablo 2
Graphics: 2D
Download: No
Needs to be bought: Yes
Simple game play that quickly satisfies a thirst for plenty of action and treasure makes Diablo a tough game to beat in the Online RPG realm. Throw in the online playability of Battle.net and you have the recipe for on of the greatest selling PC games of all-time.

Mythos
Graphics: 3D
Item Mall: Yes
Download: Yes 
Action Online RPG from the makers of Diablo and Fate.

Adventure Quest
Graphics: Yes
Download: No
Needs to be bought: No, but does have premium version. 
Little RPG with turn-based game play that is similar to the Final Fantasy series. Intended mainly as a game to play for a few minutes in your spare time.

Renaissance Kingdoms
Graphics: Text
Download: No
Needs to be bought: No
Deep RPG that allows you to go down many different paths such as being a politician, a monk, a merchant, a thief, a rebel, or even a town drunk.

DragonFable
Graphics: Yes
Download: No
Needs to be bought: No, but does have premium version.
Animated RPG that is part of the Adventure Quest universe. Like Adventure Quest, this game is played in your browser and you can make a one-time payment to get more features.

City of Eternals
Graphics: 3D
Item Mall: Yes
Download: No
Become a Vampire and explore the dark creepy world of City of Eternals.

Gekkeiju Online
Graphics: Yes
Download: Yes
Needs to be bought: No
Like Rubies of Eventide, another free fantasy online RPG/MUD that boasts 3D graphics. 

Minions of Mirth
Graphics: Yes
Download: Yes
Needs to be bought: Optional.
Can be played as a single player game or as an online RPG. You can either download the free edition or pay for the premium edition. Either way, there are no monthly fees.

Tibia
Graphics: Yes, 2D
Download: No
Needs to be bought: No, but does have premium version.
Free MMO that uses an interesting tutor system to help newer players get in the flow of the game.

Nodiatis
Graphics: Some
Download: No
Needs to be bought: No
Old school style RPG with a risk-all PvP system where PvPers risk permanent death to get items from other players.

Kingdom of Drakkar  
Graphics: Yes
Download: Yes
Needs to be bought: No
Despite the outdated graphics, it should definitely be noted that KoD does allow free access for its lowest membership plan.

Dogs of the Seas
Graphics: Yes
Download: Yes
Needs to be bought: No
Pirate multiplayer RPG where you start as a poor pirate and then plunder your way to glory. 

FaitH  
Graphics: Yes
Download: Yes
Needs to be bought: No
Browser-based MMORPG with a religious theme that offers a free edition. 

Nexus: The Kindom of the Winds 
Graphics: Yes
Download: Yes
Needs to be bought: No
Explore a mysterious world based on Asian mythology. Been around since 1998.

Dransik 
Graphics: Yes
Download: Yes
Needs to be bought: No
The classic version of the game that became Ashen Empires is now being offered for free. 

Hallway Wars
Graphics: No
Download: No
Needs to be bought: No
Choose to be a part of a stereotypical high school clique such as the jocks, nerds, stoners, or cheerleaders. 

Archmage: Reincarnation From Hell
Graphics: No
Download: No
Needs to be bought: No
Free browser-based MMORPG that pits you as a reincarnated mage who has the ability to research spells and assemble armies in a quest for domination. 

Elysarian Kingdoms 
Graphics: No
Download: No
Needs to be bought: No
Browser-based MMORPG set in a fantasy world filled with a plethora of different races. Note that some features like marriages have not been implemented yet. 

Stick Adventures Online
Graphics: Yes
Download: Yes
Needs to be bought: No
You adventure as a stick man through a wide variety of locations such as distant planets, forests, and even Washington D.C. in various eras.

TerraWorld
Graphics: Yes
Download: Yes
Needs to be bought: No
A 2D RPG with cartoon graphics, guilds, tournaments, capture the flag games, and bounties on players' heads.

Aranock Online
Graphics: Yes
Download: Yes
Needs to be bought: No
Based on the former fantasy RPG known as Astonia 2 aka Mercenaries of Astonia. 

Castle Quest 2
Graphics: No
Download: No
Needs to be bought: No
Wizards seek to control the world though the use of powerful creatures and magic items.

B.O.T.S.
Graphics: No
Download: No
Needs to be bought: No
Get a bot, train it, and then battle other bots in this semi-real-time text based game. Interesting concept since there are several TV shows with this same theme.

EUO
Graphics: No
Download: No
Needs to be bought: No
Multiplayer persistent world that was inspired by Ultima 4 and 5. Like those two classic RPGs, the graphics are very basic.   

Blood Clans
Graphics: Yes
Download: No
Needs to be bought: No
Graphical RPG where being a part of a strong clan is the only way to survive.  

Empiriana
Graphics: No
Download: No
Needs to be bought: No
Turn-based RPG that has been online for almost 10 years. 

The Five Pillars
Graphics: No
Download: No
Needs to be bought: No
Play as a mage bent on ruling the world. 

Phantasy RPG
Graphics: No
Download: No
Needs to be bought: No
RPG that allows you to train in fighting, trade, and join a clan.

The Dark Grimoire
Graphics: No
Download: No
Needs to be bought: No
Text-based fantasy game where stature and kills in an hour are ranked.  

NewAge
Graphics: Both
Download: No
Needs to be bought: No
Brower-based space game with both graphics and text.  

Utopia
Graphics: No
Download: No
Needs to be bought: No
Medieval fantasy game boasting tens of thousands of gamers that is played inside your browser. 

Materia Magica
Graphics: No
Download: No
Needs to be bought: No
Text-based online RPG where you encounter such classic monsters as trolls, goblins, giants and dragons. The best part, however, is the ability to play as an ogre!

Planetarion
Graphics: No
Download: No
Needs to be bought: No
Browser-based game in which you manage a single planet in the universe. You then have to team with other planets in your galaxy in order to survive in the massive universe. 

Graal Online
Graphics: Yes
Download: Yes
Needs to be bought: No
Massively-Multiplayer game that is very similar to the Legend of Zelda series. 

Medieval Battles
Graphics: No
Download: No
Needs to be bought: No
Text-based RPG based off of Dungeons and Dragons. 

RPG World Online
Graphics: No
Download: No
Needs to be bought: No
Free fantasy online game that plays very similar to a MMORPG.  

Roma Victor 
Graphics: 3D
Download: Yes
Needs to be bought: Yes
A non-fantasy game based in the Roman Empire. Requires a one time payment, but no monthly fees. 

A3: Awakening
Graphics: No
Download: No
Needs to be bought: No
Text-based RPG that is played in a browser and enjoys a huge fan base. This game has been around since 1997.

BARP
Graphics: No
Download: No
Needs to be bought: No
Stands for "Blood And Role Playing". Turn-based RPG with graphics that has a leader board displaying the top twenty players in terms of experience. 

Dragon Court
Graphics: No
Download: No
Needs to be bought: No
Java-based RPG with graphics that allows you to save your character and mail items to other characters.

Faldon
Graphics: Yes
Download:Yes
Needs to be bought: No
Free isometric RPG with a little of everything. This is one wacky game. Besides normal features like monster and player killing, this game allows you to play soccer? You have to pay a monthly subscription for added features.